CVE-2026-40356 — Out-of-Bounds $1

title: MIT Kerberos 5 Integer Underflow Out-of-Bounds Read Attempt — CVE-2026-40356
id: scw-2026-04-28-ai-1
status: experimental
level: critical
description: |
  This rule detects potential exploitation attempts against MIT Kerberos 5 (krb5) by monitoring for the execution of krb5-related processes. The vulnerability CVE-2026-40356 involves an integer underflow and out-of-bounds read in the gss_accept_sec_context() function when a NegoEx mechanism is registered. An unauthenticated remote attacker can trigger this, potentially leading to a process termination. Monitoring for krb5 processes is the most direct way to observe potential exploitation given the described mechanism.
author: SCW Feed Engine (AI-generated)
date: 2026-04-28
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-40356/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: process_creation
detection:
  selection:
      Image|contains:
          - 'krb5'
      condition: selection
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse